Arthritis is a painful condition that affects the joints and bones, and can make it difficult for you to move around. You might think it just affects older people, but young people can experience it too. The tissue lining the joints, like elbows and knuckles, becomes inflamed, making them stiff and swollen.

Auditory processing disorder (APD) affects how the brain interprets sound (rather than how sound is carried through the ear to the brain). It’s usually diagnosed in childhood, but sometimes it’s only picked up later as a teenager or even an adult.

A birthmark is a coloured area of skin. Some people are born with birthmarks (as the name suggests), but they can also appear in the weeks after you’re born. Many people have a birthmark of some kind but very few need treatment for them. Certain types of vascular birthmarks can be treated at Great Ormond Street Hospital (GOSH) with laser surgery.

This information for teenagers from Great Ormond Street Hospital (GOSH) is about blood poisoning (septicaemia) – a potentially life-threatening infection which is often a result of another infection in the body.

If you’re born with a cleft lip and/or palate, you’ll have a gap in your lip, palate or both. This occurs in babies when the upper lip and palate (roof of the mouth) don’t join together properly while in the womb.

Cystic fibrosis (CF) is an inherited disease which mainly affects your lungs and digestive system. It clogs up these organs with thick, sticky mucus which can lead to symptoms like a cough, chest infections and difficulty absorbing and digesting fat in food.